Cooling apparatus and cooling method for power-pack in hybrid vehicle

ABSTRACT

A cooling apparatus for a power-pack in a hybrid vehicle may include a power-pack that acquires traveling information of the vehicle and controls the operation of an engine and a motor, a low-temperature radiator that is connected with power-pack through a cooling water channel, dissipates heat from the cooling water discharged from power-pack, and is arranged in parallel with a radiator, and an electric water pump that is disposed in the cooling water channel and operated in response to an electric signal output from an ECU to circulate the cooling water through power-pack and low-temperature radiator. The cooling apparatus may also include a cooling fan. A cooling method of using the cooling apparatus may include determining engine operation, determining start of a water pump, and operating a water pump. The cooling method may also include starting a cooling fan, operating a cooling and examining a water pump.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority of Korean Patent Application Number 10-2011-0068391 filed Jul. 11, 2011, the entire contents of which application is incorporated herein for all purposes by this reference.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to a cooling apparatus in a hybrid vehicle, and more particularly, to a cooing apparatus and a cooling method for a power-pack in a hybrid vehicle which can exclusively cool a power-pack that controls energy in the hybrid vehicle.

2. Description of Related Art

As high-fuel efficiency and environment-friendly vehicles are on the rise as the main issue in the vehicle industry, hybrid vehicles using both of an engine and a motor as a power supply are spotlighted.

Such hybrid vehicles are equipped with a power-pack, which is an individual control device, to control driving of the engine and the motor and the power-pack collects traveling information of the vehicle and determines which one of the engine and the motor is used for traveling.

Since the power-pack generates heat in operation, the heat should be removed so that the power-pack can keep operating without being damaged.

In particular, a mild hybrid vehicle that greatly depends on the engine uses engine cooling water to cool the power-pack.

FIG. 1 shows a cooling apparatus for a power-pack in a hybrid vehicle according to the related art. Referring to FIG. 1, a common engine cooling apparatus that circulates cooling water between an engine 111 and a radiator 112 with a mechanical water pump 113 while controlling the cooling water with a thermostat 114 is shown. A cooling water channel additionally diverges from the outlet of radiator 112 and the cooling water is circulated in a power-pack 121 by an electric water pump 123, in the engine cooling apparatus. A portion of the cooling water discharged out of engine 111 is controlled such that it circulates in a heater by a valve 116 to be used for heating the interior.

However, with the cooling apparatus for a power-pack in a hybrid vehicle according to the related art, the cooling water discharged out of radiator 112 is directly circulated to power-pack 121. Accordingly, the cooling performance reduces and an energy loss is large due to the operation of electric water pump 123. The cooling water discharged from radiator 112 is relatively lower in temperature than the cooling water discharged from engine 111, but the temperature is still high, such that it is not suitable for cooling and the cooling performance is correspondingly decreased. For example, the cooling water temperature of power-pack 121 is controlled within 95° C. to 100° C. when middle or more load is applied to engine 111, such that it can be seen that the cooling performance considerably decreases.

Since it is required to keep electric water pump 123 operating, a large amount of energy loss is generated.

There is a limit in the traveling area of the hybrid vehicle due to the problem.

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

SUMMARY OF INVENTION

Various aspects of the present invention have been made in an effort to provide a cooling apparatus and a cooling method for a power-pack in a hybrid vehicle that is individually and efficiently controlled to cool a power-pack of a hybrid vehicle.

One aspect of the present invention provides is directed to provide a cooling apparatus for a power-pack in a hybrid vehicle. Various exemplary cooling apparatuses according to the present invention include a power-pack, a low-temperature radiator, and a pump, such as an electric water pump. The power-pack controls the operation of an engine and a motor by acquiring traveling information of the vehicle. The low-temperature radiator is connected with the power-pack through a cooling channel, such as the cooling water channel, dissipates heat from the cooling water discharged from the power-pack, and is arranged in parallel with the radiator. The electric water pump is disposed in the cooling water channel and operated in response to an electric signal output from an Electronic Control Unit (ECU) to circulate the cooling water or other suitable cooling fluids through the power-pack and the low-temperature radiator.

A cooling fan that is controlled by the ECU to introduce the external air to the low-temperature radiator may be further included.

The cooling fan may be controlled selectively by a Pulse Width Modulation (PWM) control that controls the rotation speed of the cooling fan in consideration of the temperature of the power-pack and the speed of the vehicle or an On/Off control that controls the operation of the cooling fan.

The low-temperature radiator may be positioned ahead of the radiator in the vehicle.

The electric water pump may be controlled such that the number of revolution is determined by the temperature of the power-pack.

Another aspect of the present invention is directed to a cooling method for a power-pack for a hybrid vehicle. Various exemplary cooling methods of the present invention for controlling the cooling apparatus for a power-pack may include determining start of a water pump, operating a water pump, and determining engine operation. The step of determining start of a water pump determines whether the temperature of a power-pack is above a first temperature which is set to start the electric water pump, by acquiring traveling information of a hybrid vehicle. The step of operating a water pump operates the electric water pump such that the cooling water or other suitable cooling fluids circulate through the power-pack and the low-temperature radiator if the temperature of the power-pack is above the first temperature in the step of determining start of a water pump. The step of determining engine operation determines whether the engine of the hybrid vehicle is in operation and proceeds to the step of determining start of a water pump when the engine is in operation.

Various exemplary cooling methods of the present invention may further include determining start of a cooling fan that determines whether the temperature of the power-pack is above a second temperature, wherein determining start of a cooling fan is performed after determining start of a water pump and the second temperature is set higher than the first temperature; and operating a cooling fan that operates the cooling fan if the temperature of the power-pack is above the second temperature in determining start of a cooling fan.

PWM control that controls the rotation speed of the cooling fan in consideration of the temperature of the power-pack and the speed of the vehicle or On/Off control that controls the operation of the cooling fan is selectively applied in operating a cooling fan.

Examining a water pump that determined whether there is an error in the electric water pump may be performed before the determining start of a water pump, and determining start of a water pump is performed when it is determined that the electric water pump may be in a normal state in examining a water pump.

Determining entry of a safety mode that determines whether the temperature of the power-pack is above a first temperature is performed when it is determined that the electric water pump is not in a normal state in examining a water pump. Operating in a safety mode that operates the power-pack in a safety mode is performed when it is determined that the temperature of the power-pack is above the first temperature in the determining entry of a safety mode. Operating in a normal mode that operates the power-pack in the normal mode is performed when it is determined that the temperature of the power-pack is equal to or below the first temperature in determining entry of a safety mode.

The number of revolution of the electric water pump is controlled by the power-pack and determined by the temperature of the power-pack in operating a water pump.

According to the various exemplary cooling apparatuses and cooling methods for a power-pack in a hybrid vehicle, it is possible to improve cooling performance by independently circulating the cooling water at low temperature to the power-pack, since a main radiator that cools the cooling water discharged out of the engine and the sub-radiator that exclusively cools the power-pack are separated.

The temperature of the cooling water circulating in the power-pack is considerably lower than that of the cooling water from the engine, resulting in the increases of the efficiency of the power-pack.

The apparatus can be operated in a high-temperature area, such that it is possible to expand available area where the hybrid vehicle can travel.

Since it is possible to design the elements in the power-pack at low permissible temperature, the degree of freedom in design increases.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual view diagram showing a cooling apparatus for a power-pack in a hybrid vehicle according to the related art.

FIG. 2 is a conceptual view diagram showing an exemplary cooling apparatus for a power-pack in a hybrid vehicle according to the present invention.

FIG. 3 is a flowchart showing an exemplary cooing method for a power-pack in a hybrid vehicle according to the present invention.

It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

One aspect of the present invention is directed to a cooling apparatus for a power-pack in a hybrid vehicle. Hereinafter, an exemplary cooling apparatus for a power-pack in a hybrid vehicle according to the present invention is described in detail with reference to the accompanying drawings.

A cooling apparatus for a power-pack in a hybrid vehicle according to various embodiments of the present invention is disposed independently from a common engine cooling apparatus that circulates cooling water or other suitable cooling fluids between an engine 11 and a radiator 12 with a pump such as a mechanical water pump 13.

That is, the cooling apparatus for a power-pack in a hybrid vehicle according to various embodiments of the present invention, as shown in FIG. 2, includes a power-pack 21, a low-temperature radiator 22 that is connected with power-pack 21 through a cooling fluidic channel, such as a cooling water channel, and dissipates the heat of cooling water or other cooling fluids, and a pump such as an electric water pump 23 that is disposed in the cooling water channel between power-pack 21 and low-temperature radiator 22 and circulates the cooling water.

Power-pack 21 is a component of a hybrid vehicle that controls energy for driving the engine and the motor of a hybrid vehicle. Power-pack 21 generates heat by driving of a vehicle. If the temperature of the power-pack 21 exceeds a predetermined temperature, the parts in power-pack 21 may be damaged and the efficiency may be reduced. Thus, power-pack 21 should be cooled to a temperature below the predetermined temperature.

Low-temperature radiator 22 is connected with power-pack 21 through the cooling water channel, which forms a circuit allowing the cooling water or other suitable cooling fluids to circulate through power-pack 21 and low-temperature radiator 22. In this exemplary configuration, cooling water from the engine 11 flows to the radiator 12 and the heat of the cooling water is dissipated by the radiator 12, whereas cooling water from the power-pack 21 flows to the low-temperature radiator 22 and the heat of the cooling water is dissipated by the low-temperature radiator 22. The radiator 22 is designated as the low-temperature radiator because the temperature of the cooling water from the power-pack 21 is typically lower than that of the cooling water from the engine 11.

Low-temperature radiator 22 in general has a capacity smaller than that of radiator 12 and may be positioned in parallel with and/or ahead of radiator 12. Such construction allows the cooling water passing through low-temperature radiator 22 comes in contact with the external air first, because the cooling water is lower in temperature than the cooling water passing through radiator 12. If radiator 12 is positioned ahead of low-temperature radiator 22, the external air is heated by contact with radiator 12 and then comes in contact with low-temperature radiator 22, such that heat exchange performance decreases; therefore, low-temperature radiator 22 may be positioned ahead of radiator 12.

A pump, such as an electric water pump 23 is disposed in the cooling water channel connecting power-pack 21 with low-temperature radiator 22. Electric water pump 23, which is operated in response to an electric signal, operates when an operation signal is supplied from the outside to circulate the cooling water.

This configuration may further provide a cooling fan 24 to promote heat dissipation of radiator 12 and low-temperature radiator 22. Cooling fan 24 promotes cooling of the cooling water by blowing the external air to low-temperature radiator 22, when the cooling water cannot be cooled only by circulation of the cooling water passing through low-temperature radiator 22 and when the required cooing amount is large, such as when a vehicle travels at a low speed.

Electric water pump 23 and cooling fan 24 are controlled by an Electronic Control Unit (ECU). ECU 25 determines whether electric water pump 23 or cooling fan 24 operates on the basis of temperature information received from power-pack 21 (a), and sends a control signal to operate electric water pump 23 (b) or cooling fan 24 (c). For example, when the temperature of power-pack 21 is inputted, ECU determines the number of revolution of electric water pump 23 which corresponds to the temperature of power-pack 21 and outputs a control signal corresponding to the voltage control amount fitting to the number of revolution, using a protocol, such as Controller Area Network (CAN) or Local Interconnect Network (LIN).

When controlling cooling fan 24, ECU 25 controls cooling fan 24, using Pulse Width Modulation (PWM) control or On/Off control, by determining the voltage control amount for operating cooling ran 24 in consideration of the vehicle speed and the temperature of power-pack 21. That is, the voltage control amount is determined on a table made in advance, reflecting the vehicle speed and the temperature of power-pack 21, and is selectively used for the PWM control or the On/Off control. It is possible to control the amount of air flowing inside through cooling fan 24 by controlling the speed of a motor that operates cooling fan 24 through the PWM control, or operate cooling fan 24 through the On/Off control every time cooling fan 24 needs to operate.

Reference numerals ‘15’ and ‘16’ indicate a heater and a valve that are used for heating the interior by using the heat of the cooling water of engine 11.

Another aspect of the present invention is directed to a cooling method for cooling a power-pack of a hybrid vehicle. A cooling method according to various embodiments of the present invention is as follows.

A cooling method of a power-pack of a hybrid vehicle according to various embodiments of the present invention, as shown in FIG. 3, includes determining start of a water pump (S120), operating a water pump (S130), and determining engine operation (S160). Determining start of a water pump (S120) determines whether the temperature of the cooing water is above a first temperature T1 set to start electric water pump 23, operating a water pump (S130) operates electric water pump 23 when the temperature of the power-pack is above first temperature T1, determining engine operation (S160) determines whether engine 11 of the hybrid vehicle operates, and determining start of water pump (120) is performed again when engine 11 is in operation.

Determining start of water pump (S120) determines whether the temperature of the cooling water circulating through power-pack 21 and low-temperature radiator 22 is above first temperature T1 that is set to start electric water pump 23. When the temperature is above first temperature T1, electric water pump 23 is operated such that the cooling water circulates through power-pack 21 and low-temperature radiator 22, thereby cooling power-pack 21 that generates heat. As electric water pump 23 operates, the cooling water takes heat from power-pack 21 and the heat is dissipated through low-temperature radiator 22 while the cooling water circulates between power-pack 21 and low-temperature radiator 22, such that power-pack 21 can maintain an appropriate temperature.

On the other hand, when the temperature of power-pack 21 is equal to or below first temperature T1, electric water pump 23 is not operated. This is because efficiency is high when power-pack 21 operates at an appropriate temperature range, and accordingly, when the temperature of power-pack 21 is equal to or below first temperature T1, electric water pump 23 is not operated until power-pack's temperature raises to above the appropriate temperature range.

It is preferable to perform examining a water pump (S110) that determines whether electric water pump 23 is in the normal state, before performing determining start of a water pump (S120). For example, it is examined whether ECU 25 can normally control electric water pump 23 by sensing disconnection or a short circuit of a control signal line that electrically connects ECU 25 with electric water pump 23. Operating a water pump (S130) that is described below is performed only when it is determined that electric water pump 23 is in the normal state in examining a water pump (S110).

Operating a water pump (S130) allows the cooling water to circulate between power-pack 21 and low-temperature radiator 22 by operating electric water pump 23 when the temperature of power-pack 21 is above first temperature T1. As the cooling water circulates through power-pack 21 and low-temperature radiator 22, the cooling water takes heat from power-pack 21 and dissipates the heat through low-temperature radiator 22, such that power-pack 21 maintains at an appropriate temperature range.

Determining engine operation (S160) determines whether engine 11 is in operation and performs determining start of a water pump (S120) when engine 11 is in operation, or finishes the control when engine 11 has stopped.

Meanwhile, when the temperature of power-pack 21 is above a set temperature, it is difficult to cool power-pack 21 only by circulating the cooling water through power-pack 21 and low-temperature radiator 22 with electric water pump 23. To effectively cool power-pack 21, determining start of a cooling fan (S140) and operating a cooling fan (S150) that operates cooling fan 24 are performed to promote cooling by operating cooling fan 24.

Determining start of a cooling fan (S140) determines whether the temperature of power-pack 21 is above a second set temperature T2. Second temperature T2 is set higher than first temperature T1 and is used as a determination basis for additionally operating cooling fan 24 when power-pack 21 cannot be sufficiently cooled only by simple circulation of the cooling water.

Operating cooling fan (S150) additionally operates cooling fan 24 when it is determined that the temperature of power-pack 21 is above second temperature T2 in determining start of cooling fan (S140). The temperature of power-pack 21 is naturally above first temperature when being above second temperature T2, such that cooling fan 24 is additionally operated, with electric water pump 23 operating. As cooling fan 24 operates, the external air is introduced to low-temperature radiator 22, such that the heat dissipation performance of low-temperature radiator 22 increases and the cooling performance of power-pack 21 is improved. When the vehicle speed is low, it is possible to operate cooling fan 24 even if the amount of external air introduced to low-temperature radiator 22 is small. Accordingly, the variables of controlling cooling fan 24 are the temperature of the power-pack and the speed of the vehicle.

Meanwhile, when it is determined that electric water pump 23 is in the abnormal state in examining a water pump (S110), determining entry of a safety mode (S170) that determines whether the temperature of power-pack 21 is above first temperature T1 is performed.

When it is determined that the temperature of power-pack 21 is equal to or below first temperature T1 in determining entry of a safety mode (S170), it is not necessary to cool power-pack 21. In this case, electric water pump 23 is not operated and the process proceeds to operating in a normal power-pack mode (S172).

Meanwhile, when it is determined that the temperature of power-pack 21 is above first temperature T1 in determining entry of a safety mode (S170), the cooling water is circulated by electric water pump 23 or cooling fan 24 is operated, power-pack 21 is operated in safety mode (S171).

For convenience in explanation and accurate definition in the appended claims, the terms upper or lower, front or rear, inside or outside, and etc. are used to describe features of various embodiments with reference to the positions of such features as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. 

1. A cooling apparatus for a power-pack in a hybrid vehicle that circulates cooling water discharged from an engine by connecting the engine with a radiator through a first cooling water channel, the cooling apparatus comprising: a power-pack that acquires traveling information of the vehicle and controls an operation of the engine and a motor; a low-temperature radiator connected with the power-pack through a second cooling water channel and arranged in parallel with the radiator, the low-temperature radiator dissipating heat of the cooling water discharged from the power-pack; and an electric water pump disposed in the second cooling water channel and operated in response to an electric signal output from an Electronic Control Unit (ECU) to circulate the cooling water through the power-pack and the low-temperature radiator.
 2. The cooling apparatus as defined in claim 1, further comprising a cooling fan that is controlled by the ECU to introduce an external air to the low-temperature radiator.
 3. The cooling apparatus as defined in claim 2, wherein the cooling fan is selectively controlled by a Pulse Width Modulation (PWM) control that controls a rotation speed of the cooling fan in consideration of the temperature of the power-pack and a speed of the vehicle or by an On/Off control that controls an operation of the cooling fan.
 4. The cooling apparatus as defined in claim 1, wherein the low-temperature radiator is positioned ahead of the radiator in the vehicle.
 5. The cooling apparatus as defined in claim 1, wherein the electric water pump is controlled such that a number of revolution is determined by a temperature of the power-pack.
 6. A cooling method of using the cooling apparatus as defined in claim 1, comprising: determining start of a water pump that determines a temperature of the power-pack and starts the electric water pump if the temperature of the power-pack is above a first temperature; operating a water pump that operates the electric water pump such that the cooling water circulates through the power-pack and the low-temperature radiator if the temperature of the power-pack is above the first temperature in determining start of a water pump; and determining engine operation that determines whether the engine of the vehicle is in operation and proceeds to determining start of a water pump when the engine is in operation.
 7. The cooling method as defined in claim 6, further comprising: determining start of a cooling fan that determines whether the temperature of the power-pack is above a second temperature, wherein determining start of a cooling fan is performed after determining start of a water pump and the second temperature is set higher than the first temperature; and operating a cooling fan that operates the cooling fan if the temperature of the power-pack is above the second temperature in determining start of a cooling fan.
 8. The cooling method as defined in claim 7, wherein a Pulse Width Modulation (PWM) control that controls a rotation speed of the cooling fan in consideration of the temperature of the power-pack and a speed of the vehicle or an On/Off control that controls an operation of the cooling fan is selectively applied in operating a cooling fan.
 9. The cooling method as defined in claim 6, further comprising: examining a water pump that determines whether there is an error in the electric water pump, wherein examining a water pump is performed before determining start of a water pump, and determining start of a water pump is performed if the electric water pump is in a normal state in examining a water pump.
 10. The cooling method as defined in claim 9, further comprising: determining entry of a safety mode that determines whether the temperature of the power-pack is above the first temperature, wherein determining entry of a safety mode is performed if the electric water pump is not in the normal state in examining a water pump; operating in a safety mode that operates the power-pack in the safety mode if the temperature of the power-pack is above the first temperature in determining entry of a safety mode; and operating in a normal mode that operates the power-pack in the normal mode if the temperature of the power-pack is equal to or below the first temperature in determining entry of a safety mode.
 11. The cooling method as defined in claim 6, wherein the number of revolution of the electric water pump is controlled by the power-pack and determined by the temperature of the power-pack in operating a water pump. 